Does a downloaded offline mix only play right through once, and then require refreshing to allow it to play again?

I downloaded 4 mixes for holidays, thinking I could play them whilst away, but after playing for quite a while they seemed to be trying to contact the network in order to continue playing.

Any help appreciated.

They should work more than that. But, every so often, I think it makes you redo downloaded mixes to verify the DRM. I had one of my mixes taken off my phone, and it basically said I needed to redownload it.

I'm pretty sure it says somewhere in the app or when it needs to that they need to be refreshed every month but only once a month I listen to one of my offline playlists loads and it rarely has to download